The bicubic spline interpolation is an extension of cubic interpolation for interpolating data points on a two-dimensional regular grid. For more algorithm details, please see `bicubic`_. Its implementation is essential to perform interpolation according to the x-direction, and then to interpolate in the y-direction. Then the desired result can be obtained.
.._`bicubic`: https://en.wikipedia.org/wiki/Bicubic_interpolation
As shown in the figure below, the interpolation implementation includes 2 parts: init and calcu.
- The init mainly implements parameter pre-processing and some functions of cubic spline interpolation in x-direction.
- The calcu completes cubic spline interpolation in the x-direction according to the input x and results of the init, and then completes cubic spline interpolation in the y-direction according to the obtained result and the input y to obtain an output result.
